I think the Nasa stats only started about 1968...onwards.... (...

I think the Nasa stats only started about 1968...onwards.... ( using their Sats in space )

More reliable stats would come from Temperature stations in the Uk and Europe from about 1710 and on wards....

An anywhere in the world with reliable and continuous readings using thermometers in a specific place for at least 300 hundred years..

When a reliable thermometer was developed....and slowly refined...